Drive force transmission device having air channels and image forming apparatus

ABSTRACT

A drive force transmission device includes a frame that supports therein plural gears transmitting a rotational drive force and that has a flat portion extending in a direction intersecting a direction in which the rotational drive force is transmitted. The drive force transmission device has an air channel that allows air sucked from an outside of the frame to pass therethrough so as to exhaust the air to the outside of the frame.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a Division of application Ser. No. 14/944,641 filed Nov. 18,2015, which in turn claims the benefit of Japanese Patent ApplicationNo. 2015-103411 filed May 21, 2015. The disclosure of the priorapplications is hereby incorporated by reference herein in its entirety.

BACKGROUND Technical Field

The present invention relates to a drive force transmission device andan image forming apparatus.

SUMMARY

According to an aspect of the present invention, a drive forcetransmission device includes a frame that supports therein plural gearstransmitting a rotational drive force and that has a flat portionextending in a direction intersecting a direction in which therotational drive force is transmitted. The drive force transmissiondevice has an air channel that allows air sucked from an outside of theframe to pass therethrough so as to exhaust the air to the outside ofthe frame.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiment of the present invention will be described indetail based on the following figures, wherein:

FIG. 1 is a schematic sectional view of an internal structure of animage forming apparatus;

FIG. 2A is a perspective view of a drive force transmission side of adrive force transmission device, and FIG. 2B is a perspective view of anair channel side of the drive force transmission device;

FIG. 3A is a front view of the drive force transmission device, and FIG.3B is a rear view of the drive force transmission device;

FIG. 4A illustrates flow paths of air channels of the drive forcetransmission device, FIG. 4B is a cross-sectional view illustratingarrangement of the air channels and gears of the drive forcetransmission device, and FIG. 4C illustrates part IVC of FIG. 4B;

FIG. 5 is a rear view of the air channel side of the drive forcetransmission device illustrating arrangement of the gears;

FIG. 6A is a perspective view of an inner surface side of the apparatusbody to which the drive force transmission device is attached, and FIG.6B is an enlarged view of part of the drive force transmission device;

FIG. 7A is a perspective view of a rear side of the apparatus body towhich the drive force transmission device is attached, and FIG. 7B is anenlarged view of part of the drive force transmission device; and

FIG. 8 illustrates flows of air in the apparatus body.

DETAILED DESCRIPTION

Next, an exemplary embodiment and a specific example according to thepresent invention will be described with reference to the drawings infurther detail below. It should be understood that the present inventionis not limited to the exemplary embodiment and the specific example.

Furthermore, it should be noted that the drawings referred to in thefollowing description are schematically illustrated and not to scale,and illustration of elements not required for the description is omittedas appropriate for ease of understanding.

For ease of understanding of the description hereafter, the front-reardirection, the left-right direction, and the vertical direction arerespectively defined as the X direction, the Y direction, and the Zdirection in the drawings.

(1) An Overall Structure and Operations of an Image Forming Apparatus

FIG. 1 is a schematic sectional view of an internal structure of animage forming apparatus 1 for which a drive force transmission device100 according to an exemplary embodiment is used.

An overall structure and operations of the image forming apparatus 1 aredescribed below with reference to the drawings.

The image forming apparatus 1 includes a controller 10, a sheet feeddevice 20, photosensitive units 30, developing devices 40, a transferdevice 50, and a fixing device 60. An output tray 1 a is formed on anupper (+Z direction) surface of the image forming apparatus 1. Sheets ofpaper on which images are recorded are output to and received by theoutput tray 1 a.

The controller 10 includes components such as an image-forming-apparatuscontroller 11, a data converter 12, a light exposure controller 13, anda power source unit 14. The image-forming-apparatus controller 11controls operations of the image forming apparatus 1. The data converter12 prepares image data in response to a print processing request. Thelight exposure controller 13 controls turning on of lighting by a lightexposure devices LH. The power source unit 14 applies high voltages tocomponents such as charging rollers 32, developing rollers 42, firsttransfer rollers 52, and a second transfer roller 53, which are to bedescribed later. The power source unit 14 also supplies power to thelight exposure devices LH, the sheet feed device 20, the fixing device60, and sensors and the like provided in these components.

The data converter 12 converts print information received from anexternal information transmission device (for example, a personalcomputer or the like) into image information for forming a latent imageand outputs this image information to the light exposure devices LH inthe form of drive signals at preset timing. The light exposure devicesLH according to the present exemplary embodiment each include alight-emitting-diode (LED) head in which plural LEDs are linearlyarranged in a main scanning direction.

The sheet feed device 20 is provided at a bottom portion of the imageforming apparatus 1. The sheet feed device 20 includes a sheet loadingplate 21. Many sheets of paper P are loaded on an upper surface of thesheet loading plate 21. Each of the sheets P serves as a recordingmedium. The position in the width direction of the sheets P loaded onthe sheet loading plate 21 is determined by a regulating plate (notillustrated). These sheets P are drawn forward (−X direction) one afteranother from the uppermost sheet by a sheet drawing member 22. Each ofthe sheets P having been drawn is then transported to a nip of aregistration roller pair 23.

The photosensitive units 30 are arranged parallel to one another above(+Z direction) the sheet feed device 20 and include respectivephotosensitive drums 31, which are rotated. The charging roller 32, thelight exposure device LH, the developing device 40, the first transferroller 52, and a cleaning blade 34 are arranged around each of thephotosensitive drums 31 in a rotating direction of the photosensitivedrum 31. A cleaning roller 33 that cleans a surface of the chargingroller 32 is disposed so as to face and be in contact with the chargingroller 32.

The developing device 40 includes a developing housing 41 that containsdeveloper therein. The developing roller 42 and a pair of transportaugers 44A and 44B are disposed in the developing housing 41. Thedeveloping roller 42 that serves as a developer holding body faces thephotosensitive drum 31. The transport augers 44A and 44B are disposed ona lower rear side of the developing roller 42. The transport augers 44Aand 44B agitate the developer and transport the developer to thedeveloping roller 42 side. A layer thickness regulating member 46 thatregulates the thickness of a layer of the developer is disposed near thedeveloping roller 42.

There are no big differences between the structures of the developingdevices 40 except for the developer contained in the developing housings41. Yellow (Y), magenta (M), cyan (C), and black (K) toner images areformed by the respective developing devices 40.

The surface of the rotating photosensitive drum 31 is charged by thecharging roller 32. An electrostatic latent image is formed on thecharged surface of the photosensitive drum 31 by latent-image forminglight emitted from the light exposure device LH. The electrostaticlatent image formed on the photosensitive drum 31 is developed into atoner image by the developing roller 42.

The transfer device 50 includes an intermediate transfer belt 51 and thefirst transfer rollers 52. The toner images of the colors formed on thephotosensitive drums 31 of the photosensitive units 30 are transferredonto the intermediate transfer belt 51 so as to be superposed on oneanother. The first transfer rollers 52 sequentially transfer (firsttransfer) the toner images of the colors formed by the photosensitiveunits 30 onto the intermediate transfer belt 51. The transfer device 50further includes the second transfer roller 53 and anintermediate-transfer-belt cleaner 54. The second transfer roller 53collectively transfers (second transfer) the toner images of the colorshaving been transferred onto the intermediate transfer belt 51 so as tobe superposed on one another onto the sheet P that serves as the exampleof the recording medium. The intermediate-transfer-belt cleaner 54removes residual toner attracted to the intermediate transfer belt 51.

The toner images of the colors formed on the photosensitive drums 31 ofthe photosensitive units 30 are sequentially electrostaticallytransferred (first transfer) onto the intermediate transfer belt 51 bythe first transfer rollers 52 to each of which a specified transfervoltage is applied from the power source unit 14 or the like controlledby the image-forming-apparatus controller 11. Thus, superposed tonerimages formed of the toner images of the colors superposed one anotherare formed.

Due to a movement of the intermediate transfer belt 51, the superposedtoner images on the intermediate transfer belt 51 are transported to aregion (second transfer portion TR) where the second transfer roller 53is disposed. When the superposed toner images are transported to thesecond transfer portion TR, the sheet P is supplied from the sheet feeddevice 20 to the second transfer portion TR at timing adjusted to thetransportation of the superposed toner images. A specified transfervoltage is applied from the power source unit 14 or the like controlledby the image-forming-apparatus controller 11 to the second transferroller 53, thereby collectively transferring the superposed toner imagesfrom the intermediate transfer belt 51 onto the sheet P fed by theregistration roller pair 23 and guided by a transport guide.

The residual toner on the surfaces of the photosensitive drums 31 isremoved by the cleaning blades 34 and collected in a waste tonercontainer (not illustrated). The surfaces of the photosensitive drums 31are charged again by the charging rollers 32. Remaining matter that hasnot been removed by the cleaning blades 34 and is attracted to thecharging rollers 32 is collected on the surfaces of the cleaning rollers33, which are rotated and in contact with the charging rollers 32, andaccumulated.

The fixing device 60 includes a heating module 61 and a pressure module62. A fixing nip N (fixing region) is defined in a region where theheating module 61 and the pressure module 62 are in pressure contactwith each other.

The sheet P onto which the toner images have been transferred by thetransfer device 50 but have not yet been fixed is transported to thefixing device 60 through the transport guide. The sheet P transported tothe fixing device 60 is subjected to pressure and heat applied theretoby a pair of the heating module 61 and the pressure module 62. Thus, thetoner images are fixed.

The sheet P on which a fixed toner image has been formed is output froman output roller pair 69 to the output tray 1 a in the upper surface ofthe image forming apparatus 1.

(2) The Drive Force Transmission Device

FIG. 2A is a perspective view of a drive force transmission side of thedrive force transmission device 100, and FIG. 2B is a perspective viewof an air channel side of the drive force transmission device 100. FIG.3A is a front view of the drive force transmission device 100, and FIG.3B is a rear view of the drive force transmission device 100. FIG. 4Aillustrates flow paths of air channels 120 of the drive forcetransmission device 100, FIG. 4B is a cross-sectional view illustratingarrangement of the air channels 120 and gears G in the drive forcetransmission device 100, and FIG. 4C illustrates part IVC of FIG. 4B.FIG. 5 is a rear view of the air channel 120 side of the drive forcetransmission device 100 illustrating arrangement of the gears G.

The structure of the drive force transmission device 100 is describedbelow with reference to the drawings.

(2.1) An Overall Structure of the Drive Force Transmission Device

The drive force transmission device 100 includes a frame 110, the pluralgears G, drive transmission members 130, and the air channels 120. Theplural gears G transmit rotational drive forces of drive motors M. Thedrive transmission members 130 transmit rotation of the gears G torotating bodies.

As illustrated in FIGS. 2A and 3A, the plural drive transmission members130 supported on the drive force transmission side of the drive forcetransmission device 100 project from the frame 110. The drivetransmission members 130 include drum drive members 131 (illustrated inFIGS. 6A and 6B), developing drive members 132, and a belt drive member133. The drum drive members 131 rotate the photosensitive drums 31 thatserve as an example of the rotating bodies. The developing drive members132 rotate the developing devices 40. The belt drive member 133 rotatesthe intermediate transfer belt 51 of the transfer device 50. The drivetransmission members 130 transmit the rotational drive forces of thedrive motors M to the respective rotating bodies through the pluralgears G rotatably supported in the frame 110.

Plural air inlets 121 a, 121 b, 121 c, and 121 d of the air channels 120are integrally formed in the frame 110 on the drive force transmissionside of the drive force transmission device 100. The plural air inlets121 a, 121 b, 121 c, and 121 d are provided for the photosensitive units30 and the developing devices 40 of the respective colors (yellow (Y),magenta (M), cyan (C), and black (K)) and connected to a single airoutlet 122, which will be described later.

As illustrated in FIGS. 2B and 3B, the air channels 120 are formed on anopposite side to the drive force transmission side of the drive forcetransmission device 100. One end of each of the air channels 120 isconnected to a corresponding one of the air inlets 121 a, 121 b, 121 c,and 121 d that are open on the drive force transmission side. The otherend sides of the air channels 120 are merged with one another andconnected to the single air outlet 122.

(2.2) The Air Channels

As illustrated in FIGS. 4A to 4C, the frame 110 has a flat portion 111and a recess portion 113. The flat portion 111 extends in a directionintersecting a direction of transmission of the rotational drive forces.The recess portion 113 is formed by a continuous wall portion 112 thatis integrally formed with the frame 110 and stands erect on the flatportion 111 of the frame 110.

As illustrated in FIGS. 4B and 4C, the recess portion 113 is defined bythe wall portion 112. This recess portion 113 and a cap member 114disposed on and joined to the wall portion 112 on an opening portion 113a form the air channels 120 having a continuous closed sectional shapethat connects the air inlets 121 a, 121 b, 121 c, and 121 d to the airoutlet 122.

The frame 110 and the wall portion 112, which defines the recess portion113 of the air channels 120, are integrally formed of synthetic resin.From the viewpoint of strength, examples of the synthetic resin materialmay include resin such as, for example, acrylonitrile butadiene styrene(ABS), polycarbonate (PC), or polyethylene terephthalate (PET) which arefilled with glass fiber. The cap member 114 is also formed of syntheticresin such as ABS or polypropylene (PP).

As illustrated in FIG. 4A, the air inlets 121 a and 121 b are disposedcloser to the air outlet 122 than the air inlets 121 c and 121 d.

According to the present exemplary embodiment, the air inlet 121 a facesthe photosensitive unit 30 and the developing device 40 that are usedfor the yellow (Y) color, and the air inlet 121 b faces thephotosensitive unit 30 and the developing device 40 that are used forthe magenta (M) color. Toner cloud is likely to be generated with theyellow toner and the magenta toner. In particular, the yellow toner, acharging property of which is low compared to the toner of the othercolors, is likely to scatter. Thus, by disposing the air inlet and theair outlet near the yellow (Y) side, the toner cloud may be moreefficiently collected.

As illustrated in FIGS. 4B and 5, the plural gears G that transmit therotational drive forces of the drive motors M to the drive transmissionmembers 130 are disposed and supported at positions further to a rearside than the rear surface of the flat portion 111 where the airchannels 120 are formed and at positions further to an outer side thanthe outer surface of the cap member 114 of the air channels 120.

According to the present exemplary embodiment, gears G1 that transmitthe rotational drive forces of the drive motors M to the drum drivemembers 131 are disposed and supported at positions further to the outerside than the outer surface of the cap member 114 of the air channels120.

Gears G2 (not illustrated) that transmit the rotational drive forces ofthe drive motors M to the developing drive members 132 are disposed andsupported at positions further to the rear side than the rear surface ofthe flat portion 111 where the air channels 120 are formed.

(3) Attachment of the Drive Force Transmission Device to the ApparatusBody

FIG. 6A is a perspective view of an inner surface side of the apparatusbody with the drive force transmission device 100 attached, and FIG. 6Bis an enlarged view of part of the drive force transmission device 100.FIG. 7A is a perspective view of a rear side of the apparatus body withthe drive force transmission device 100 attached, and FIG. 7B is anenlarged view of part of the drive force transmission device 100. FIG. 8illustrates flows of air in the apparatus body.

Attachment of the drive force transmission device 100 to the apparatusbody and the flows of air are described below with reference to thedrawings.

As illustrated in FIGS. 6A and 6B, the drive force transmission device100 is secured to a housing F of the apparatus body in a state in whichthe drive motors M are attached to the drive force transmission device100 and the drive transmission members 130 project from the housing F tothe inner surface side of the apparatus body. In this state, the airinlets 121 a, 121 b, 121 c, and 121 d of the air channels 120 are openon the inner surface side of the apparatus body.

The photosensitive units 30, the developing devices 40, and the transferdevice 50 are respectively attached to the drive transmission members131, 132, and 133 of the drive force transmission device 100 from afront surface side of the apparatus body (see FIG. 1), so that therotational drive forces of the drive motors M are transmitted to thephotosensitive units 30, the developing devices 40, and the transferdevice 50.

As illustrated in FIGS. 7A and 7B, a filter member 140 and an exhaustfan 150 are provided on the rear surface side of the apparatus bodywhere the drive force transmission device 100, to which the drive motorsM are attached, is attached. The filter member 140 is connected to theair outlet 122 of the drive force transmission device 100. Air exhaustedthrough the air channels 120 and the air outlet 122 of the drive forcetransmission device 100 is exhausted to the outside of the apparatusbody through the filter member 140 by the exhaust fan 150.

The filter member 140 allows the air exhausted from the air outlet 122to pass therethrough and traps the toner cloud and foreign mattercontained in the air, thereby purifying the air exhausted by the exhaustfan 150 to the outside of the apparatus body.

The exhaust fan 150 according to the present exemplary embodiment is ofa centrifugal type including a centrifugal impeller (not illustrated).The exhaust fan 150 compresses the air having passed through the filtermember 140 and exhausts the air to the outside of the apparatus bodythrough a discharge port 151.

As illustrated in FIG. 8, in the image forming apparatus 1 that includesthe drive force transmission device 100 having the structure asdescribed above, the air in the apparatus body including regions aroundthe photosensitive units 30, the developing devices 40, and the transferdevice 50 disposed in the apparatus body, flows as follows: the air issucked through the air inlets 121 a, 121 b, 121 c, and 121 d, passesthrough the air channels 120, and is introduced into the filter member140 through the air outlet 122.

After the toner cloud and the foreign matter contained in the air havebeen trapped by the filter member 140, the air is compressed by andexhausted to the outside of the apparatus body by the exhaust fan 150(see arrows R of FIG. 8).

The drive force transmission device 100 according to the presentexemplary embodiment has air channels 120. The air channels 120 connectthe air inlets 121 a, 121 b, 121 c, and 121 d, which are open on thedrive force transmission side of the flat portion 111 of the frame 110supporting the gears G and the drive transmission members 130, to theair outlet 122. The air outlet 122 of the air channels 120 is connectedto the exhaust fan 150 through the filter member 140.

Thus, the dimension of the apparatus body in the depth direction may bereduced and blow-off of the toner cloud may be suppressed. Furthermore,by forming the air channels 120 in the drive force transmission device100, the drive force transmission device 100 may be efficiently cooled.

The plural gears G that transmit the rotational drive forces of thedrive motors M to the drive transmission members 130 are disposed andsupported at positions further to the rear side than the rear surface ofthe flat portion 111 where the air channels 120 are formed and atpositions further to the outer side than the outer surface of the capmember 114 of the air channels 120.

Accordingly, the air that is sucked from the inside of the apparatusbody and contains the toner cloud and the foreign matter passes throughthe air channels 120 that are separated from the gears G1 and G2 andhave the closed sectional shape. This may suppress attraction of thetoner cloud and the foreign matter to the gears G1 and G2.

The foregoing description of the exemplary embodiment of the presentinvention has been provided for the purposes of illustration anddescription. It is not intended to be exhaustive or to limit theinvention to the precise forms disclosed. Obviously, many modificationsand variations will be apparent to practitioners skilled in the art. Theembodiment was chosen and described in order to best explain theprinciples of the invention and its practical applications, therebyenabling others skilled in the art to understand the invention forvarious embodiments and with the various modifications as are suited tothe particular use contemplated. It is intended that the scope of theinvention be defined by the following claims and their equivalents.

What is claimed is:
 1. A drive force transmission device comprising: aframe that supports therein a plurality of gears transmitting arotational drive force and that has a flat portion extending in adirection intersecting a direction in which the rotational drive forceis transmitted, wherein the drive force transmission device has an airchannel that allows air sucked from an outside of the frame to passtherethrough so as to exhaust the air to the outside of the frame. 2.The drive force transmission device according to claim 1, wherein theframe has one surface and another surface, wherein a plurality of airinlets are formed on a one surface side of the frame, wherein a singleair outlet is formed on another surface side of the frame, and whereinthe air channel has a continuous closed sectional shape that connectsthe plurality of air inlets to the single air outlet.
 3. The drive forcetransmission device according to claim 1, wherein a cap member isprovided, wherein a wall portion is provided so as to stand erect on theflat portion of the frame, wherein a recess portion having an opening isdefined by the wall portion, and wherein the air channel is a closedstructure formed by the recess portion and the cap member that isdisposed on and joined to the wall portion on an opening side of therecess portion.
 4. The drive force transmission device according toclaim 1, wherein a plurality of air inlets and an air outlet areprovided, and wherein at least one of the plurality of air inlets isdisposed closer to the air outlet than the other air inlet of theplurality of air inlets or the other air inlets of the plurality of airinlets.
 5. The drive force transmission device according to claim 1,wherein a cap member having an outer surface is provided, wherein theflat portion has a rear surface, and wherein the plurality of gears aredisposed and supported at a position or positions further to a rear sidethan the rear surface of the flat portion where the air channel isformed and at a position or positions further to an outer side than theouter surface of the cap member for the air channel.
 6. The drive forcetransmission device according to claim 1, wherein the air channel isformed in the frame formed of synthetic resin.
 7. An image formingapparatus comprising: an apparatus body; the drive force transmissiondevice according to claim 1 having an air outlet; a drive motor thatrotates the plurality of gears of the drive force transmission device; arotating body that is rotated by receiving the rotational drive forcefrom the drive force transmission device; a filter member connected tothe air outlet of the drive force transmission device; and an exhaustfan that exhausts the air having passed through the air channel of thedrive force transmission device to an outside of the apparatus bodythrough the filter member and the air outlet of the drive forcetransmission device.